Anisotropic expansion of the universe and the anisotropy and linear polarisation of the cosmic microwave background

1974 ◽  
Vol 29 (2) ◽  
pp. 415-426 ◽  
Author(s):  
A. M. Anile
Keyword(s):  
Cosmic Microwave Background ◽  
Microwave Background ◽  
Anisotropic Expansion ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Linear Polarisation

scholarly journals PROBING THE ANISOTROPIC EXPANSION HISTORY OF THE UNIVERSE WITH COSMIC MICROWAVE BACKGROUND

2012 ◽  
Vol 27 (24) ◽  
pp. 1250144 ◽  
Author(s):  
RANJITA K. MOHAPATRA ◽  
P. S. SAUMIA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Cosmic Microwave Background ◽  
Background Radiation ◽  
Microwave Background ◽  
Anisotropic Expansion ◽  
Microwave Background Radiation ◽  
Expansion Stage ◽  
History Of ◽  
Density Perturbations ◽  
Expansion Of The Universe ◽  
The Universe

We propose a simple technique to detect any anisotropic expansion stage in the history of the universe starting from the inflationary stage to the surface of last scattering from the cosmic microwave background radiation (CMBR) data. We use the property that any anisotropic expansion in the universe would deform the shapes of the primordial density perturbations and this deformation can be detected in a shape analysis of superhorizon fluctuations in CMBR. Using this analysis we obtain the constraint on any previous anisotropic expansion of the universe to be less than about 35%.

Polarimetry of the Cosmic Microwave Background from the Antarctic Plateau

2002 ◽  
Vol 19 (3) ◽  
pp. 313-317
Author(s):  
G. Sironi ◽  
E. Battistelli ◽  
G. Boella ◽  
F. Cavaliere ◽  
M. Gervasi ◽  
...  
Keyword(s):  
Cosmic Microwave Background ◽  
Thermal History ◽  
Microwave Background ◽  
Terra Nova Bay ◽  
Celestial Pole ◽  
History Of ◽  
The Antarctic ◽  
The Universe ◽  
Recombination Epoch ◽  
Linear Polarisation

AbstractDetection of linear polarisation at a level of 1 ppm or less, associated to the anisotropy of the cosmic microwave background, will confirm the cosmological origin of the observed anisotropy and provide information on the thermal history of the universe between the recombination epoch and now. In particular, detection of polarisation can help in deciding if the evolution of the universe included a reionisation epoch. We present the Mk3 model of our correlation polarimeter, an improved version of a system which has already been used for observations of the region of sky around the South Celestial Pole from Antarctica (in 1994 at Terra Nova Bay and in 1998 at Dome C).

scholarly journals COSMIC PARALLAX IN ELLIPSOIDAL UNIVERSE

2011 ◽  
Vol 26 (16) ◽  
pp. 1169-1181 ◽  
Author(s):  
L. CAMPANELLI ◽  
P. CEA ◽  
G. L. FOGLI ◽  
L. TEDESCO
Keyword(s):  
Large Scale ◽  
Type I ◽  
Microwave Background ◽  
Preferred Direction ◽  
Anisotropic Expansion ◽  
Cosmic Microwave Background Anisotropy ◽  
Expansion Of The Universe ◽  
Axis Of Symmetry ◽  
Planar Symmetry ◽  
The Universe

The detection of a time variation of the angle between two distant sources would reveal an anisotropic expansion of the universe. We study this effect of cosmic parallax within the ellipsoidal universe model, namely a particular homogeneous anisotropic cosmological model of Bianchi type I, whose attractive feature is the potential to account for the observed lack of power of the large-scale cosmic microwave background anisotropy. The preferred direction in the sky, singled out by the axis of symmetry inherent to planar symmetry of ellipsoidal universe, could in principle be constrained by future cosmic parallax data. However, that will be a real possibility if and when the experimental accuracy will be enhanced at least by two orders of magnitude.

scholarly journals A buyer’s guide to the Hubble constant

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Paul Shah ◽  
Pablo Lemos ◽  
Ofer Lahav
Keyword(s):  
Cosmological Model ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Hubble Constant ◽  
Microwave Background ◽  
A Value ◽  
Expansion Of The Universe ◽  
Edwin Hubble ◽  
The Universe ◽  
Georges Lemaître

AbstractSince the expansion of the universe was first established by Edwin Hubble and Georges Lemaître about a century ago, the Hubble constant $$H_0$$ H 0 which measures its rate has been of great interest to astronomers. Besides being interesting in its own right, few properties of the universe can be deduced without it. In the last decade, a significant gap has emerged between different methods of measuring it, some anchored in the nearby universe, others at cosmological distances. The SH0ES team has found $$H_0 = 73.2 \pm 1.3 \; \;\,\hbox {kms}^{-1} \,\hbox {Mpc}^{-1}$$ H 0 = 73.2 ± 1.3 kms - 1 Mpc - 1 locally, whereas the value found for the early universe by the Planck Collaboration is $$H_0 = 67.4 \pm 0.5 \; \;\,\hbox {kms}^{-1} \,\hbox {Mpc}^{-1}$$ H 0 = 67.4 ± 0.5 kms - 1 Mpc - 1 from measurements of the cosmic microwave background. Is this gap a sign that the well-established $${\varLambda} {\text{CDM}}$$ Λ CDM cosmological model is somehow incomplete? Or are there unknown systematics? And more practically, how should humble astronomers pick between competing claims if they need to assume a value for a certain purpose? In this article, we review results and what changes to the cosmological model could be needed to accommodate them all. For astronomers in a hurry, we provide a buyer’s guide to the results, and make recommendations.

scholarly journals Mapping the Dark Energy Equation of State

2005 ◽  
Vol 216 ◽  
pp. 59-66
Author(s):  
Eric V. Linder
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Density ◽  
Cosmic Microwave Background ◽  
Structure Formation ◽  
Energy Equation ◽  
Microwave Background ◽  
Redshift Surveys ◽  
Expansion Of The Universe ◽  
The Universe

The acceleration of the expansion of the universe has deep implications for structure formation, the composition of the universe, and its fate. Roughly 70% of the energy density is in a dark energy, whose nature remains unknown. Mapping the expansion history through supernovae, mapping the geometry of the universe and formation of structure through redshift surveys, and mapping the distance to recombination through the cosmic microwave background provide complementary, precise probes of the equation of state of the dark energy. Together these next generation maps of the cosmos can reveal not only the value today, but the redshift variation, of the equation of state, providing a critical clue to the underlying physics.

scholarly journals Cosmic Microwave Background Anisotropy at Degree Angular Scales and the Thermal History of the Universe

1997 ◽  
Vol 480 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Paolo de Bernardis ◽  
Amedeo Balbi ◽  
Giancarlo De Gasperis ◽  
Alessandro Melchiorri ◽  
Nicola Vittorio
Keyword(s):  
Cosmic Microwave Background ◽  
Thermal History ◽  
Microwave Background ◽  
Cosmic Microwave Background Anisotropy ◽  
History Of ◽  
The Universe

scholarly journals GRAVITY HEATS THE UNIVERSE

2009 ◽  
Vol 18 (14) ◽  
pp. 2201-2207
Author(s):  
ADAM MOSS ◽  
DOUGLAS SCOTT
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Energy Conservation ◽  
Cosmic Microwave Background ◽  
Initial Conditions ◽  
Gravitational Instability ◽  
Simplified Model ◽  
Microwave Background ◽  
Average Temperature ◽  
The Universe

Structures in the Universe grew through gravitational instability from very smooth initial conditions. Energy conservation requires that the growing negative potential energy of these structures be balanced by an increase in kinetic energy. A fraction of this is converted into heat in the collisional gas of the intergalactic medium. Using a toy model of gravitational heating, we attempt to link the growth of structure in the Universe with the average temperature of this gas. We find that the gas is rapidly heated from collapsing structures at around z ~ 10, reaching a temperature > 106 K today, depending on some assumptions of our simplified model. Before that there was a cold era from z ~ 100 to ~10 in which the matter temperature was below that of the cosmic microwave background.

The TopHat Cosmic Microwave Background Anisotropy Experiment

2005 ◽  
Vol 201 ◽  
pp. 65-70
Author(s):  
Robert F. Silverberg ◽  
Keyword(s):  
Cosmic Microwave Background ◽  
Large Scale ◽  
Background Radiation ◽  
High Sensitivity ◽  
Microwave Background ◽  
Long Duration ◽  
Cosmic Microwave Background Anisotropy ◽  
Microwave Background Radiation ◽  
The Universe ◽  
Large Scale Structure Formation

We have developed a balloon-borne experiment to measure the Cosmic Microwave Background Radiation anisotropy on angular scales from ˜50° down to ˜20′. The instrument observes at frequencies between 150 and 690 GHz and will be flown on an Antarctic circumpolar long duration flight. To greatly improve the experiment performance, the front-end of the experiment is mounted on the top of the balloon. With high sensitivity, broad sky coverage, and well-characterized systematic errors, the results of this experiment can be used to strongly constrain cosmological models and probe the early stages of large-scale structure formation in the Universe.

scholarly journals The question on origin of the universe and Big Bang

2011 ◽  
Vol 2 ◽  
pp. 67-70
Author(s):  
Krishna Raj Adhikari
Keyword(s):  
Cosmic Microwave Background ◽  
Background Radiation ◽  
Scientific Evidence ◽  
Big Bang ◽  
Cosmic Microwave Background Radiation ◽  
Microwave Background ◽  
Microwave Background Radiation ◽  
Physics Department ◽  
The Universe ◽  
Origin Of The Universe

School of thought is the theory of creation (theism) and school of thought deals with the random chance of evolution (atheism) about the origin of the universe and origin of the life. In the race of proof of the hypothesis, the theism has no scientific evidence and reliable proof, on the other hand atheism based on the scientific observable evidence. The latest theory of origin of the universe by Big Bang is more believable and supported by some scientific evidence such as Doppler effect on light, Hubble observation and result of the expanding the universe and observation of the cosmic microwave background radiation(CMBR). Paper briefly discussing about the origin of the universe and the Bing Bang.Key words: Big bang; Doppler; Cosmic microwave background radiation(CMBR)The Himalayan Physics Department of Physics, PN Campus, Pokhara Nepal Physical Society, Western Regional ChapterVol.2, No.2, May, 2011Page: 67-70Uploaded Date: 1 August, 2011

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